Penis and scrotum
Inflammatory lesions
Melanosis and lentiginosis


Topic Completed: 1 February 2010

Revised: 13 February 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: (Melanosis OR lentiginosis) penis
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Cite this page: Chaux A, Cubilla AL. Melanosis and lentiginosis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/penscrotumlentiginousmel.html. Accessed March 22nd, 2019.
Definition / general
Clinical features
  • Benign, although associated with melanoma

Penile melanosis:
  • Large, often single, flat and pigmented macule with irregular borders
  • Pigmentation may be associated with Laugier-Hunziker syndrome (Int J Dermatol 2004;43:571)

Penile lentiginosis:
  • Penile lentigines are 0.2 - 2 cm, oval to irregular lesions with uniform or variegated pigmentation
  • Areas of depigmentation are characteristic
  • Lesions are scattered on shaft or glans
  • Clinically may resemble an atypical melanocytic lesion
  • May be associated with Cowden disease (J Cutan Med Surg 2001;5:228), Bannayan-Riley-Ruvalcaba syndrome (J Am Acad Dermatol 2005;53:639)
Clinical images

AFIP

Melanosis

Microscopic (histologic) description
Penile melanosis:
  • Melanocytic hyperplasia, hyperpigmentation of basal epithelium and otherwise normal epithelium

Penile lentiginosis:
  • Elongation of rete ridges with basal layer hyperpigmentation, slight melanocytic hyperplasia, epithelial hyperplasia and stromal melanophages, no atypia (J Am Acad Dermatol 1990;22:453)
  • In hyperpigmented areas, there are increased number of melanocytes along the basal layer
  • Lymphocytes, which are found in close apposition, destroy melanocytes and surrounding keratinocytes lack pigmentation (Pigment Cell Res 1992;5:404)
Microscopic (histologic) images

AFIP

Melanosis

Differential diagnosis
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